DNA interstrand cross-linking (ICL) agents have been widely applied in medicines, biology, biochemistry, and material sciences.  However, low ICL efficiency and dearth of easily on-time analysis method limit its bio-application. Here, we report a highly efficient, directly detectable, and photoreversible DNA cross-linking reaction between coumarin moiety and thymidine. DNA ICLs were formed via a photoinduced [2+2] cycloaddition upon 350 nm irradiation. The cross-linking efficiency and rate constants were affected by the linker units between coumarin moiety and phosphate group as well as by flanking sequences. A two-carbon or longer linker (4  and 5 ) is optimal, which leads to quantitative DNA cross-linking (> 98%). ICL formation by coumarin scaffolds exhibits a kinetic preference when flanked by an A:T base pair as opposed to a G:C pair (10 times slower). DNA ICL formation induced by coumarin is highly reversible. DNA ICLs formed by 350 nm irradiation can be cleaved to the single stranded DNA with 254 nm irradiation, and 80% cross-linking yield was still obtained even after 3 cycles. Most importantly, completely quenched fluorescence of coumarin after ICL formation allows for monitoring ICL formation progress on time via fluorescence spectroscopy. This method was also used to detect DNA mutation with good discriminating effect. Over all, a fast, quantitative, easily detectable, and photoswitchable cross-linking reaction via coumarin moiety was developed, which will serve as mechanistic probes and tools for bio-research.

Highly efficient, directly detectable, and photoreversible DNA interstrand cross-linking by coumarin derivatives

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.